Author: Minke Bergsma
Bergsma, Minke, 2020 Surgical- and imaging techniques to optimize volar plating in distal radius fractures, Flinders University, College of Medicine and Public Health
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The aim of this thesis was to improve volar plating for distal radius fractures by reducing tendon related peri-operative iatrogenic complication rate, both on the volar and dorsal side of the wrist with the use of (new) imaging techniques. We have specifically focused on preventing plate- and screw mal-positioning leading up to these complications. On the dorsal side, the protruding screws can cause extensor tendon attrition and rupture. On this side of the wrist, there is no room for error as the closest tendons are on average only half a millimeter away from the dorsal bony cortex (chapter 3). Without the use of views additional to the standard lateral and antero-posterior views, in 40% of patients at least one screw was found to be protruding the dorsal cortex 0.5 mm or more (chapter 1). The Dorsal Tangential View, in South Australian popularized as the Lleyton Hewitt View –after the famous ‘Come On’ cry of the Adelaide tennis
player- has been advocated in recent literature to detect protruding screws intraoperatively based on pre-clinical and small clinical studies (chapter 5). We found out the efficacy of this view is high; in 31% of the distal radius fracture surgeries, intraoperative management was changed based on this view (chapter 6). However, when using post-operative tri-planar CT-reconstructions to identify remaining protruding
screws in patients that where checked intra-operatively with the DTV, the sensitivity of this view appeared to be only 52% (chapter 7). We explored three-dimensional fluoroscopy (3DF) for detection of dorsal screw penetration and could not conclude that 3DF outperforms DTVs for this purpose. We postulated that the accuracy of DTV might improve after training. And indeed, inter-observer reliability, sensitivity, specificity and accuracy of this view improved after training (chapter 9).
On the volar side, mal-positioning of the volar plate with respect to the watershed line can lead to plate prominence and interference with the volar flexor tendons. In literature we found eight different interpretations of the definition the ‘watershed line’ (chapter 4). With the use of Q3DCT-imaging we identified the true watershed line. We postulated that the ulnar radial prominence, situated on the watershed line on the ulnar side of the radius, is the best reference marker for this line as it is easy to
palpate for the surgeon (chapter 10). When using the most volar point of the volar distal radius on a lateral x-ray as watershed line, we found that plate design directs plate (mal) positioning with respect to this watershed line; the use of the DVR plate resulted in a safer plate positioning compared to the VA-LCP plate. (chapter 2). In 11 some individuals, the tendons are much closer so the surgeon should keep in mind
the danger of hardware to the flexor tendons even when staying well proximal from the watershed line (chapter 3).
Keywords: distal radius fracture, volar plating, dorsal tangential view, watershed line
Subject: Surgery thesis
Thesis type: Doctor of Philosophy
Completed: 2020
School: College of Medicine and Public Health
Supervisor: Ruurd Jaarsma